引言
遇到需要转屏的功能，查资料刚好看到一篇iOS强制横屏或强制竖屏，不过发现里面的方法有点太不可取，做了下修改。
为什么push或者pop后的viewController 不响应所有的 旋转方法？
这里是因为，根视图（rootController）不是你的viewController，你去监听肯定是没有的，这里你就需要监听根视图，比如说下面的例子中的nav。
BaseNavCtl ---- 这代码里，是为了让MultiQualityViewController横屏，这里就举这一个栗子
#import <UIKit/UIKit.h>
@interface BaseNavCtl : UINavigationController
@end
BaseNavCtl .m
//
// BaseNavCtl.m
// MGMediaDemo
//
// Created by ciome on 2017/4/5.
// Copyright © 2017年 MiGu. All rights reserved.
//
#import "BaseNavCtl.h"
#import "MultiQualityViewController.h"
@interface BaseNavCtl ()
@end
@implementation BaseNavCtl
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (UIInterfaceOrientationMask)supportedInterfaceOrientations {
// 获取topCtl
UIViewController *ctl = self.topViewController;
// 进行后续区分
if([ctl isKindOfClass:[MultiQualityViewController class]]){
return UIInterfaceOrientationMaskLandscape;
}
else {
return UIInterfaceOrientationMaskAll;
}
}
- (BOOL)shouldAutorotate
{
return true;
}
- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated
{
// 获取topCtl
UIViewController *ctl = viewController;
// 在进入之前强制旋转设备
if([ctl isKindOfClass:[MultiQualityViewController class]]){
[self interfaceOrientation:UIInterfaceOrientationLandscapeRight];
}
[super pushViewController:viewController animated:animated];
}
// 强制转屏
- (void)interfaceOrientation:(UIInterfaceOrientation)orientation
{
if ([[UIDevice currentDevice] respondsToSelector:@selector(setOrientation:)]) {
SEL selector = NSSelectorFromString(@"setOrientation:");
NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:[UIDevice instanceMethodSignatureForSelector:selector]];
[invocation setSelector:selector];
[invocation setTarget:[UIDevice currentDevice]];
int val = orientation;
// 从2开始是因为0 1 两个参数已经被selector和target占用
[invocation setArgument:&val atIndex:2];
[invocation invoke];
}
}
/*
#pragma mark - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
}
*/
@end
AppDelegate --- BaseNavCtl成为rootController
self.window= [[UIWindow alloc]initWithFrame:[[UIScreen mainScreen]bounds]];
BaseNavCtl *navigationController = [[BaseNavCtl alloc]initWithRootViewController:[[DemoMainViewController alloc]init]];
self.viewController= navigationController;
self.window.rootViewController=self.viewController;
[self.window makeKeyAndVisible];
为什么这样写
这样写的好处是，可以把整个APP内的视图方向管理，都集中在baseNavCtl这个类里面；当然，这样也必然增加了每次匹配的消耗，但由于每次nav只有一个topViewCtl ，所以可以做唯一判别减少匹配消耗，这里就不贴代码了。
